To simplify the expression 7a + 2b + 5a + b, we first need to combine like terms. Like terms are terms that have the same variable raised to the same power.
1. **Identify like terms**: In our expression, we have:
- 7a and 5a, which are both terms with the variable a.
- 2b and b (remember that b can be rewritten as 1b), which are both terms with the variable b.
2. **Combine the a terms**: We add 7a and 5a:
- 7a + 5a = 12a
3. **Combine the b terms**: Next, we add 2b and 1b:
- 2b + 1b = 3b
4. **Write the simplified expression**: Now, putting it all together, we can write:
- 12a + 3b
So, the simplified form of the expression 7a + 2b + 5a + b is 12a + 3b.